Ammeter



July 25, l933- J. E. ESHBAUGH v 1,919,504

AMMETER Filed Feb. 2, 1931 2 Sheets-Sheet l July 25, 1933, J. E. ESHEAUGH 1,9199504 AMMETER Filed Feb. 2. 19:51 2 sheets-sheet 2 gva/manioc Patented July 25, 1933 f l UNiIEo sIA-IEs PIATENTIYO@E f erv FLINL, ivrrcnienn, e. CoMPANy or MICHIGAN A' AMMETEB.

.'52 The improvements in the' ammeter consist in mountlng a d1e cast frame inside the.l he Jframe has a usuali ammeter casing. recessed or-holloW base and hollow upstandlng posts at the ends thereof. A pair of io contacts pass through the rear oi the casing andthe base and secure thertWo together.` A' flat'V iece of metal havin@` its ends'se-4 cured to the contacts and to thebase and the intermediate part coiled, forms the conl'ductor for4 the ammeter and a shuntconnects the two contacts immediately at the points of attachment to the conductor. These parts are rifidlA secured toOether and form al unit. The pointer swinging mechanism,

20`inagnet, and dialrarealso interrelated in a second unit Which is mounted on top ofthe posts of the frame. 'The unit comprises frame or plate having a suitable portion thereof formedto -zreceive theendsof a horse#- 25:1shoe magnet. A tongue bent from the plateV and formed .with a right-angularly .bent end portion forms a means tor mounting the shaft of the pointer. he magnet 1s placed in the recess in the plate and thel dial then. SOplaced over the magnet. A pair of screws pass Vthrough the dial and plate/andi intoV the'posts to secure the unit kto the'base and in'cooperative relation with the conductor. Referring to the drawings: l Figure 1 meter Ywith parts broken away to illustrate certain portions of the invention.`

Figure 2 is an expanded View ofthe ain-- meter parts.

Figure 3 is Figure 1. 1 y

Figure 4 is a plan view of alnodified form of ammeter mechanism with the dialrea'v Y 1s mounted. f A screw bloclr58 iss-threaded Into thel arm 54 and has'a depressionin'one end moved and shown in dotted-outline.,

Figure 5 is a side elevation of the structure of Figure4.. l Y Figure 6 is an eXpanded View of. parts of the modification of Figures' 4 and 5. Y

Referring tothe drawings,-the numeral 2 59 indicates the casingot1 the ammeter. The

1s a front elevation of the`ama 'section on the line kof casinghas the bezel 4 secured at 6 to flange 8 on the casing. The ringilO is confined-between the bezel anl casing and supports the 2 `between the insulating sheets 22. Y The bottom of the base 18 is recessed or; hollow as shown in Figure 8, the purpose ofivvhich isto accommodate the .nuts 20 ndfto decrease the amount of metal necessary in castn ing the frame. The'con'tact bolts 16 have' the contact heads 24y by'means o'f'which thev 4rd, JESSE E. ESIIBAUGH, orrrnrr, iwrIoIIIeAii, AssIeNoR'To A el SPARK PLUG CoilIPAng-g" shuntf26 and theends -28 of the"conductor i 30A are secured tothe base 18.' Intermediate its ends-28, the conductor 30 is coiledv as shovvnat32 in Figures'2 'and (if` rEhe coilv preferably hasthe recessed portion 34 to ac-..

commodate theV axle Vof the pointer. .Af suit-y ablepiece of insulation 136 is positioned be;`

tween the conductor ends 28 and the basei18.

The'en'd's of the` frame. l14comprise vthe hol- 10W uprghts 38 and 40 each of which is pro# vided with a threaded opening 42 and a re-' cessed portion'44 ,at its .upper end. SmallV projecting studs 45, one' at each end of the base 18, lit into corresponding rec'esses'in` the. casulgfbottom to position the frame relative to the casing. The parts'so far described are rigidly secured together and form .a i

unit. .1 y Y l. Y `The dial 70, magnet 82, pointerv46, and

pointer swinginglmechanism l48 are mounted Von a fra-Ine orkplate 5U and comprisea second unit. The plate 50 has thetongue '52 pressed therefrom, Which tongue is provided withV a right'fangularl'y bentend portion 54 and between :the portion l54 and plate 50 the shaft 56 vof the pointerV swinging mechanism thereof and a groovev 6() in the other, the lat? ter of `Which isto accommodate a screw-driver 1 to adjust't'he sCreW The block 58i`s-forthe the sha-ft 56* is piloted in an inwardly pressed portion, 62 of the plate 50. The pointer 46 is rigidly mounted on the shaft 56 and has integrally formed thereinv the balance weight 64. An armature 66 is also secured to the shaft 56 immediately adj acentthe pointer 46.

' A suitable opening 68 in the plate 50 accommodates the pointer 46 and allows it to extend over the dial 7 0 to swing thereover. The dial 70 has the openings72'and thevplate 50 has the openings 74 which mate withv eachl other and with the openings 42 in the post 40. Y

Suitable screws 76y extend to the openingsf?v 2 and 7 4 and are threaded into the openings 42 rigidly to hold the parts together, the plate 50 fitting in the recesses 44.. -The pla-te 50 is suitably shaped or pressed as shown at 78 in Figure 2te accommodate the ends 80 of a horseshoe magnet 82, the magnet beingl held between the dial 70 and plate 50. The dial may be permanently secured to the plate 450 by screws screwed into openings 81 and 83.

The plate 50 and the parts secured theretoV comprise the second unit of the ammeter and this unit is removable from the first unit. The advantage of this construction is that if any of the parts of the more delicate pointer unit'are damaged or broken this unitmay bev removed without disturbing the rest of the ammeter. Y u

Inthe species of Figures 4, 5'and 6, a

stamped frame 100 instead of the diecast frame V14 is used. The stamped frame is. Amountediin thevusual outer casingand is generally of U-shape -in cross-section and comprises the base 102, the web 104 and the y and to the base of the frame.v

rIhe centraly portion of the web 104 and wing'106 are open as shown at 116 toiaccommodate the pointer swinging mechanism or to provide an integral tongue `118 to form a mounting for thepointer shaft. Suitable 4recesses 120 are pressed in the upper wing 106 to accommodate the vends 80 of the magnet 82. The shaft 56 and pointer 46'v are the same as in thespecies of Figure 1 andk may be frame.

mounted in the same way or, ifk desired, the

block` 58 may be omitted as shown in Figurek 5. When the magnet 82 has been placedfin the recess 120the dial7 0 is placed thereover and secured thereto by means of the screws 7 6 f passing through openings in the dial Aand threaded into openings 122 in ears 124 formed integral with the wing portion 106 of the As in the vcase ofthespeciesof Figure 1,

the conductor 114 is formed with a coil 32- in-` termediate its ends. The conductor of the species of Figures 4 to6y is formed of a straight strip of metal and has portions bent at right angles as shown at 126 to form the contact ends of the coil 32. The forming of the conductor.` from the fiat strip of metal results in the'saving of considerable material and is to be preferred. The conductor of Figure 6 may be used with the species of Figuresltol VThe cross-sectional area of shunt 26 will not be the same for all installations for the amperages will vary and where the amperage is` low, `no shunt is required or needed. Where a shunt of' a definite cross-sectional area-will be proper for Yone installation ofthe ammeter, a second installation willf have a different current or amperage and to accommodate the shunt to these different amperages, a different shunt 26 of the same shape but of a different thickness of metal is used.

The purpose of this is to use the same dies in the operation of stamping the shunt.

I'claim:l -v 1.*In an electrical measuring instrument,

a casing, a frame secured in the casing and having a plurality of posts, contacts mounted in said frame, a conductor secured to said contacts .and extending away' from said frame, a plate securedV to, said posts, a magnet supported on Vsaid plate, a pointerv and axle sup-port formed on said plate, and a dial secured to said postsV over said plate. y

2. A'In an electrical measuring instrument, a casing, a frame unit includinga frame having a plurality of posts, a plurality of contacts secured to the frame, and a conductor secured to the contacts and frame, a pointer unit including a supporting frame secured to the posts, a shaft support formed on said supporting frame, a pointer secured to the shaft, a magnet supported on the supporting frame and av dial secured to the posts over the supporting frame. y Y

3. `In an electrical measurmg'instrument, a

casing, a frame unit including a frame hav-*xy ing a plurality of posts and resting on its base against'the casing back, apairof con-V tacts passing through the casing and base and rigidly secured thereto, a shunt connecting said contacts, a conductor coil secured to `said contacts, and means mounted on said posts 'to indicate the current passing through the conductor. Y

4. In anelectrical measuring instrument,

a casing, a pointer unit comprising a plate,

a pointer shaft, a tongue bent from the said plate to forma support for the shaft, a

pointer rigid withthe shaft, and a magnet mounted on the Yplate to bias the pointer, a frame in the casing, a plurality of uprights on said frame for supporting said unit, and a conductor secured to saidframe.

" JESSE E. ESHBAUGH. 

